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Traffic Light Simulator

Classic red-yellow-green sequence with timing.

beginner25 min

Components Needed

Arduino UNO

Red, Yellow, Green LEDs

3× 220Ω resistors

Breadboard & wires

Circuit Diagram & Wiring

Add your circuit diagram image here.

Red LED → pin 8 via 220Ω.
Yellow LED → pin 9 via 220Ω.
Green LED → pin 10 via 220Ω.
All cathodes → GND.

Arduino Sketch (.ino)

traffic-light.ino

const int R = <span style="color:#79b8ff">8span>, Y = <span style="color:#79b8ff">9span>, G = <span style="color:#79b8ff">10span>;

void setup() {
  pinMode(R, OUTPUT);
  pinMode(Y, OUTPUT);
  pinMode(G, OUTPUT);
}

void loop() {
  digitalWrite(R, HIGH); delay(<span style="color:#79b8ff">3000span>); digitalWrite(R, LOW);
  digitalWrite(G, HIGH); delay(<span style="color:#79b8ff">3000span>); digitalWrite(G, LOW);
  digitalWrite(Y, HIGH); delay(<span style="color:#79b8ff">1000span>); digitalWrite(Y, LOW);
}